Impregnating process



1932- J. ZAVERTNlK. J R

IMPREGNATING PROCESS Filed Dec. 19, 1928 INVENTOR: I 105 mm j BY ATTORNPatented Och-g5, 1932 UNITED STATES PATENT oFncE JOSEPH ZAVERTNIK, JR,0! HARRINGTON PARK, NEW JERSEY, ASSIGNOB 1'0 m BARRETT 00., 01' NEWYORK, N. Y., A CORPORATION OF NEW YORK manena'rmo rnocnss Applicationfiled December 19, 1928. Serial Io. 827,090.

My invention relates to a process for the impregnation of porous fabricssuch as paper, felt, strawboard, cloth or the like. More particularly myinvention pertains to the production of roofing paper, artificialshingles and similar materials by the impregnation of porous fabric withhot tar or asphalt, but it is generall applicable to the impregnation ofporous abrics with any saturant in fluid condition. Y o

, In the production of roofing paper or artificial shingles, acontinuous impregnation process is usually employed. A roll of felt orother suitable fabric is unwound by machinery and the moving felt ispassed through a bath of a fluid saturant after which it travels out ofthe bath and moves in the air for a sufiicient time to permit the hotfluid saturant to harden. Squeeze rolls are employed to express theexcess saturant and to give any desired surface appearance to theproduct.

My invention is particularly useful in the continuous .t e of.saturation process described thoug it is also apphcable to a batchprocess in which only one piece of fabric is treated at a time.

One of the advantages of my process is that the fabric need" not beimmersed in the saturant. This feature permits a close control of theamount of saturant employed and a similar control of the degree ofsaturation attained. Another advantage of my process lies in the use ofa partial vacuum to promote saturation. The saturant maybe deliveredwith considerable penetrating force to one side of the fabric and thispenetration may be assisted by maintaining a partial vacuum on thereverse side of the fabric. Other advantages will become apparent.

My invention may best be understood by reference to the appended drawingin which letters and legends are used to describe the process as appliedto the saturation of a roll of felt or other porous fabric by means of asuitable apparatus which is shown in cross section. V

In the drawing (A) is a sheet of fabric under oing treatment and (B) isan idler roll. pre erably steam heated, over which it passes. Afterleaving the idler (B), the fabric (A) passes downward as indicated bythe arrow and contacts with a revolving drum (C). As shown in thedrawing this drum has a perforated or foraminous surface. The drum (C)is rotated, in the direction indicated by the arrows, by a gearing orother suitable means. drum (C3 is stationary drum (D) which is supporteby a hollow axle (E) and radial spokes (o), and (K)- The drum (C) isequipped with suitable heads which are not shown in the cross-sectionaldrawing. The supporting axle (E) of drum (D) penetrates these heads. Theerforated or foraminous surface of drum (8) is preferably of such awidth that the fabric (A) will completely cover the perforations.

A partial vacuum is maintained in that portion of the annular space(L)between drums (C) and (D) that is shown'between baflles (M) and (N).This partial'vacuum is maintained by a suction on the space inside axle(E) and is transmitted to space (L) by the hollow radial spokes (H),(I),.and (J). As the drum (0) revolves, the partial vacuum is maintainedin space (L) by means concentrically positioned within of the bafiles(M) and (N) which closely fit 7 against the inside surface of drum '(C).The ends of this annular space are sealed by baflles fastened to drum(D) and extending from (M) to (N) at each end of drum (D).

he semi-circular outward edges of these baflies fit closely against theinside of revolving drum (G). The'fabric (A), after passing around thedrum (0), rises and passes over idler roll (0) and through wringer.rolls (P) and (Q) which act to squeeze out excess saturant.

In the operation of the process, the fabric (A) passes over idler (B)and its top (drumside) surface is coated with saturant by spray pipe (R)at a rate suflicient to effectively cov-- er the surface of the fabricwhich later comes into contact with the drum (C) An apron (S) extendsdownward from spray pipe and rests on the center line of the drum at apoint opposite the baffle (M). The purpose of the apron is to preventany saturant from spray (R) from entering the drum (C) Without havingpreviously contacted with the fabric The effect of the saturant placedon the drum side of fabric (A) by spray pipe (R) is to render the fabricpliable and to cause it to adjust itself to the surface of the drum (C).Since the fabric thus coated with saturant travels at the same speed asthe periphcry of the drum, it forms a complete and permanent sealbetween the atmosphere and that portion of the perforated or foraminousdrum (C) that includes space (L) between baffles (M) and (N).

Asthe drum (C) rotates, carrying the fabric (A) with it, the under sideof the fabric is sprayed with saturant by means of spray pipe (T) whichis shown in thedrawing as ollowing the general contour of the drum.Spray pipe (T) is supplied with saturant from tank (U) by means of pipe(V), pump (W) (diagrammatically shown) and pipe (X). Excess saturantfrom spray pipe (T) falls back into tank (U). Spray pipe (R) may besupplied with saturant from the same, or from another source.

The saturant is delivered to the bottom side of the fabric on drum (C)with considerable force which causes it to penetrate the fabric. Thepartial vacuum maintained in space (L) between drums (C) and (D) createsa differential pressure between the inner and outer surfaces of thefabric so that a sucking action is set up which promotes saturation.

The advantages of my invention thus described, are believed to beobvious. The penetration of the fabric by the saturant is aided not onlyby the penetrating force of the spray but by the differential pressurecreated, whereby the spray-applied saturant is drawn into the fabric. Myprocess thus permits a rapid and uniform saturationwith a minimumwastage of excess saturant.

In the specific form of my invention shown in the drawing the fabric (A)is saturated while passing around the lower half of the drum (C). It isobvious, however, that the movement of the drum might be reversed andthe upper half used, for saturating purposes. appropriate changes beingmade in the position of the inner drum (D) and the sprays (R) and (T).While only one spray pipe (T) is shown in the drawing it will of coursebe understood that any number of such pipes ma be used across the widthof the fabric. While I have shown the maintenance of a partial vacuum inthe appropriate section of drum (C) by means of an inner, stationary,drum equipped with hollow radial spokes, other means may be employed toproduce the partial vacuum used in my process. 7

When my invention is employed for the purpose of saturating fabric witha bituminous material such as tar. asphalt, or pitch. the saturant mustbe used while hot since it tends to solidify at normal temperatures. Insuch a case, the saturant may be readily maintained in a fluid conditionby means of heat applied; in any convenient manner to tank (U) or" itscontents. It should be noted, however, that my invention is equallyapplicable to the saturation of fabric at room temperature withsubstances that remain fluid at such temperatures.

No claim is made in this ap lication for the broad feature of renderingabric pliable and adapted to fit closely to a vacuum cylinder duringimpregnation since this is the oint invention of myself and another andis the subject of co-pending application Serial 391,- 854 filed Sept.11, 1929.

Now having described my invention, I claim 1. The process of saturatingfabrics which comprises supporting the fabric to be saturated with onesurface of the fabric in contact with a supporting member and the othersurface exposed, and sprayin excess saturant onto the exposed surface ofthe fabric from a point therebeneath while subjecting the supportedsurface of the fabric to a reduced pressure as compared with that on theexposed surface, the excess saturant supplied to the fabric draining offby gravity from the exposed surface of the fabric and the penetration ofthe remaining saturant sprayed onto the fabric being aided by thedifferential pressure, whereby the degree of saturation of the fabric iscontrolled.

2. The process of saturating felt with a bituminous saturant, whichcomprises continuously passing the felt with one side thereof in contactwith the base 'portion of a rotating foraminous support while leavingthe other side exposed, spraying excess saturant onto the exposed sideof the felt from a point therebeneath while maintaining suction on thesupported side of the felt, the saturant being supplied under pressuresufficient to penetrate the exposed side of the felt, the excesssaturant draining off by gravity from the exposed side of the felt, thepenetration of the remaining saturant sprayed onto the felt being aidedby the suction on the supported side of the felt, whereby the degree ofsaturation of the felt is controlled.

3; The process of saturating fabrics which comprises supporting thefabric to be saturated with one surface thereof in contact with aforaminous supporting member and the other surface exposed, sprayingexcess saturant onto the exposed surface of the fabric while subjectingthe supported surface of the fabric to a reduced pressure as comparedwith that on the exposed surface, excess saturant being removed from theex osed surface throughout the area thereof subjected to differentialpressure, and the penetration of the remaining saturant sprayed onto thefabric being aided by the differential pressure, whereby the degree ofsaturation of the fabric is controlled.

4. A process for impregnating fabric which comprises coating one side ofsaid fabric with a fluid saturant, passing said coated side in contactwith a perforated supporting surface, and maintaining a partial vacuumon said coated side while spraying a fluid saturant onto the other sideof said fabric.

5. A process for impregnating felt which comprises coating one side ofsaid felt with a fluid tarry saturant, passing said coated side incontact with a perforated supporting surface, and maintaining a partialvacuum on said coated side while spraying said fluid tarry saturant ontothe other side of said felt.

JOSEPH ZAVERTNIK,JR.

